A solid ball of metal has a spherical cavity inside it. When the ball is heated the volume of the cavity will A. Increase B. Decrease C. Remain unaffected D. Have its shape changed

The correct answer is A. Increase.

When a solid ball of metal is heated, the metal expands. This expansion will cause the volume of the ball to increase, including the volume of the cavity inside it.

Option B is incorrect because the volume of the cavity will increase, not decrease.

Option C is incorrect because the volume of the cavity will increase, not remain unaffected.

Option D is incorrect because the shape of the cavity will not change, only its volume.